Month: December 2022

This is opening in the boiler. It is used for cleaning and inspection purpose. Through this hole operator enters inside the boiler in idle condition.

The function of fusible plug is to extinguish the fire in the fire box, when water level in the boiler comes down the limit. It prevents from blasting the boiler, melting the tube, and overheating the fire box crown plate. The constructional details of fusible plug are shown in Figure 4.23. It is located in water space…

The function of blow-off cock is to blow down the sediments collected at the bottom of the drum or to empty the boiler or to lower down the water level in the drum. The blow-off cock is fitted at lowest portion of the boiler. The casing is provided with two flanges—one is connected to the…

The function of steam stop valve is to stop or allow the flow of steam from boiler to steam pipe or from steam pipe to supply. The opening of the valve is controlled by a hand wheel. The constructional details of steam stop valve are very simple which is shown in Figure 4.21. Figure 4.21 Steam Stop…

The function of feed check valve is to allow the flow of water under pressure from feed pump to boiler and to prevent the backflow of water in case of failure of the feed pump. The constructional details are shown in Figure 4.20. The valve rises under pressure and water is allowed to flow inside the drum.…

The function of the water level indicator is to show the water level inside the boiler drum. Totally two water level indicators are provided on the boiler drum. The constructional details are shown in Figure 4.18. One end of the glass tubes is connected to steam space and other end to water space through a hollow pipe of…

Following are the functions of high steam and low water safety valve: The constructional details of the high pressure low water safety valve are shown in Figure 4.17. The arrangement for the outer valve is similar to that of lever loaded valve. The balance or counter weight can be fixed at any position along the arm by…

Lever safety valve works on the principle of second system of lever as shown in Figure 4.16. In this valve, there is a lever which can rotate about fulcrum but its movement is limited by a guide. When moment about fulcrum due to steam pressure exceeds the moment about fulcrum due to weight applied on the lever,…

This type of safety valve is spring loaded. Spring force works against the steam pressure, when steam pressure becomes high, valve is lifted off the valve seat and steam is escaped out. A lever is attached with one end of spring as shown in Figure 4.15. When steam pressure comes down valve returns to valve seat due…

Figure 4.14 Dead Weight Safety Valve Steam pressure acting in upward direction is counter balanced by the dead weight of safety valve acting in downward direction. When steam pressure exceeds the dead weight of safety valve, valve rises from its valve seat and steam escapes into the atmosphere. The construction of dead weight safety valve is…